856 CHARLES PauL ALEXANDER 
as in many species of Limnophila and in the eriopterine series allied to 
Gonomyia (Gonomyia, Rhabdomastix, and other genera), these pits lie 
one on either side of the median line of the prescutum, at the extreme 
cephalic margin; in other groups, as in the eriopterine series allied to 
Erioptera (Erioptera, sens. str., Empeda, and other genera), they are 
found on the dorsum of the prescutum, about midlength of the segment. 
‘These pits are the double, or paired, dots of Osten Sacken. 
The pseudosutural foveae (fig. 126, B) are prominent depressions on the 
sides of the prescutum, in front, lying just above the anterior spiracles, 
Wing root Nesepimeron 
Transverse \ i 
suture Scurellurn / 
rst Scuturn i /Postnotum Fronotum 
Pr escutum ee Soe i # / Halter _Tetanoturn _ 
3 cape RVD) aserZ Tuwbhercu/aote 
“Abdominal P 
< Ttergite! 
Anterior 
spiracle 
me 
: ‘ Mf \! S) 
¢ -Abdorminal aX Bry Sout 
Prateiccs es sternite Sx : 
AGL b> ira 
( coxe Scutellum 
Head Cy ! Hiddle coxa -~Postnotam 
Fore coxa ! 
‘ /Tesosternurm 
Mesecisternum | 
Fig. 126. THORAX OF TIPULA 
A, Lateral aspect; B, dorsal aspect. Adapted from Snodgrass 
usually in the area before the ends of the short lateral stripes and at the 
sides of the longer median stripe. These structures have been called 
the humeral pits. 
The scutum is the second subdivision of the mesonotum. It lies just 
behind the V-shaped suture and is usually divided into two lateral lobes 
by a shallow median depression. 
The scutellum is the third subdivision of the mesonotum. It is a small 
transverse segment, lying just behind the lobes of the scutum and before 
the postnotum. 
The postnotum is the fourth and last subdivision of the mesonotum. 
It is a large and prominent sclerite situated behind the scutellum, appearing 
